Horizontal band saws of a variety of configurations have been used in the past. Such horizontal band saws typically include a number of common features such as a head having a pair of rotatable wheels around which a band saw blade extends. At least one of the wheels is controllably rotatable through the use of a motor. Rotation of the wheels causes the band saw blade to move across a board receiving passage of the head. A board conveyor, such as a belt, passes through the board receiving passage and below the band saw blade. A board resting on the board conveyor is fed through the head so as to be cut along its length. The height of the board conveyor relative to the band saw blade can typically be adjusted to control how the board is cut.
In many applications, such as in resaw applications involving short boards, it is desired to maximize board cutting capacity. One technique used in the past for increasing board cutting capacity has been to align multiple band saw heads in back to back fashion such that a large board may be cut lengthwise into a plurality of smaller boards. As a board is passed through such a device it is cut along its length a number of times by different band saw blades resulting in a plurality of stacked board pieces which exit the device. Such sequential band saw devices have effectively increased the cutting capacity achievable by a single machine operator. However, such band saw devices have accompanying disadvantages including relatively high cost due to the large number of band saw heads needed. Further, it has been found that as the number of band saw heads is successively increased a point is reached where board cutting capacity begins to diminish due to the increased likelihood of machine down time. In particular, when one head in a system breaks down the entire band saw line must typically be shut down while the one head is repaired. Still further, the size of such band saw devices becomes a problem as a large number of band saw heads are aligned back to back. For example, in order to cut a six inch high board into eight 3/4 inch high boards in a single pass it is necessary to align seven band saw heads back to back.
Accordingly, it is an object of the present invention to provide a horizontal band saw device and method for cutting multiple boards along their respective lengths simultaneously.
Another object of the present invention is to provide a band saw device having a band saw head with multiple board conveyors passing therethrough to provide increased board cutting capacity as compared to existing band saw devices which have band saw heads including only one board conveyor passing therethrough.
Yet another object of the present invention is to provide a band saw device and associated method in which multiple band saw heads are placed back to back, each successive band saw head including a greater number of lanes of travel than the previous band saw head.